2 Answers

You should double check to make sure all your connection points for you heat sink are nice snug with those newly installed machine screws. If the solder looks like it might be the issue, maybe go over it again with the heat gun to get it re-flowing. Also, Matt suggested 2 potential fixes for RROD issues Installed RRoD repair kit, still getting the three rings... What now?- Although the "Towel trick" sounds a little far fetched it is a good short term fix. Cheers.

You have to leave it red ring with the fan sitting on the dvd drive and on top of the tall heat sink. let it ovr heat for 30-45 minutes cool down for 15 min the turn it back on works like a charm 100% hit rate for me also check the secondary error code if it is a 0110 then it is the two ram chips under the gpu's heatsink.